Presser-foot-lifting mechanism.



No. 858,858. I PATENTBD JULY 2; 1907.

' H. H. CUMMINGS.

PRBSSER FOOT LIFTING MECHANISM.

APPLICATION rum) 16.19, 1004. 1

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'rINITED STATES PATENT OFFICE.

HENRY H. CUMMINGS, OF MALDEN, MASSACHUSETTS, ASSIGNOR TO UNION LOOKSTITCH COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

PRESSER-FOOT-LIFTING- MECHANISM.

Specification of Letters Patent.

Patented July 2, 1907.

Application filed August 19,1904:- Serial No. 221,378-

mechanism comprising, essentially, a clamp cooperating with. thePresser-bar of a machine, and actuating means for the said clamp actingin the operation of the machine to cause the clamp to grip or becomeengaged with ,the said presser-bar and then move the latter in thedirection of the length thereof. Such mechanism is employed, forinstance, for the purpose of effecting automatically the lifting of thepresser-foot alternately with the formation of the stitches in theworking of a sewing machine.

The present invention has reference to mechanism of the generalcharacter aforesaid. It is more especially designed as an improvement inautomatic presser-foot lifting mechanism. I do not, however, limitmyself to the use of the features of the invention in this preciseconnection, solely;

The invention will be explained with reference to the drawings, in whichis illustrated an embodiment thereof, and in the course of thedescription of the said embodiment the various objects and advantagesthereof will be set forth.

In the drawings,-Figure 1 shows in end elevation the head of a sewingmachine having the said embodiment of the invention applied thereto.Fig. 2 is a view thereof mainly in vertical section in the planeindicated by the dotted line 2, 2, Fig. 1, looking in the directionindicated by the arrows at the ends of such line. Fig. 3 is a viewthereof mainly in vertical section in the plane indicated by the dottedline 3, 3, Fig. 1, looking in the direction indicated by the ar- Fig. 4is a View in horizontal section in the plane indicated by the dottedline 4, 4, Fig. 3, looking in the direction indicated by the arrows atthe ends of such line. Fig. 5 shows the clamp-device'separately in sideelevation.

Having reference to the drawings,A presser-bar is shown at 1, thepresser-ioot attached to the lower end thereof being indicated at 2. Thepresser-bar is mounted,. as usual, in guide-bearings in the upper andlower portions of the head 3 of a sewing machine at the outer extremityof the arm or gooseneck 4 forming part of the frame of the said machine.To cause the presser-foot to bear against the material beneath the same,a depressing spring is applied in connection with the presser-bar, asusual. The depressing spring in the present instance is a spiral-spring5, Figs. 1., 2 and 3. It is confined between a block or collar 6, fastupon the upper end of the presser-bar above the top of the head 3, and astationary upper collar 7. For the purpose of enabling the tension ofthe said depressing-spring 5 to be varied as required, in order toadjust the pressure of the presser-foot upon the material beneath it,the upper collar 7 is provided upon the lower end of a screw 8,thethreaded stem of the latter being fitted within aninteriorly-threaded hole that is tapped through the horizontal arm of abracket 9, the said bracket being fixed to the head 3 and risingtherefrom. By turning the screw 8 in one direction or the other thecollar 7 is lowered or raised as may be necessary, and the tension ofthe spring is thereby varied in proportion as the spring 5 is compressedor relieved from compression. The screwS is provided with a lock-nut 81to prevent accidental loss of the adjustment thereof. In order toprevent the presser-bar and presser-foot from turning so as to swing thelatter into an improper position,

the collar 6 is provided with an extension 61 that is slotted asindicated in Fig. 3 to fit the upright stem of the bracket 9. The saidslotted extension is free to slide up and down the said upright stem,and hence the vertical movements of the presser-bar are not interferedwith, but lateral displacement of the presser-foot in consequence ofrotary movement of the presser-foot and presser-bar around the axis ofthe latter is obviated. To assist in alining the screw 8 and collar 7with the Presser-bar, and in preventing accidental shift horizontally ofthe horizontal arm of bracket 9 by which said screw is carried, theopposite sides of the upright stem of the said bracket are flattened, asindicated at 91, Figs. 2 and 3, for engagement with the side-walls ofthe slot in the extension of collar 6. The lower end of the stem ofbracket 9 is received in a socket 92 in the top of head 3, see Fig. 3,and removably secured therein by means of a clamping-screw 93, Fig. 2.The loosening of the said clamping -screw, and removal of the bracketaffords opportunity to withdraw the resser-bar from its guidebcarings inhead 3, after the 95 disengagement of the Presser-foot from the lowerend of the presser-baix. The parts as thus far described, and thearrangement thereof, are not directly involved in the invention, andvarious changes may be made therein in practice, if deemed desirable.

I will now proceed to describe the parts which are more immediatelyinvolved in the invention. A sleeve or block 10 is fitted upon thepresser-bar 1, within the opening at the outer end of the head 3, andbetween the upper and lower guide-bearings for the presser-bar 1 05 inthe said head. The said sleeve or block constitutes the body of theclamp which I employ. It has a sliding fit upon the presser-bar, toenable the sleeve or block and presser-bar to move vertically withrelation to each other when not locked together. At one side of thesleeve or block a slot 101, Fig. 3 is formed through the wall thereof,the said slot extending vertically throughout the greater portion of thelength of the sleeve or block, and at opposite sides of the slot thesleeve or block is formed or provided with projecting cheeks 102, 102,which are parallel with each other. The cheeks receive between themlever-members comprising the clamping-lever 11 and the actuator-lever12. The said lever-members 11 and 12 respectively are provided withpivot-pins 11]. and 121, respectively, the bearings of which areconstituted by holes that are formed through the said cheeks. Thepivot-pins occupy holes that extend transversely through the saidlever-members.

For the purposeof enabling each lever-member to be tightened upon thepivotal pin which occupies the hole therein, so as to grip and hold thesaid pin in place to guard against accidental endwise movement, a slitis made in the lever-member, leading from the exterior surface of thelatter to the transverse hole, and a screw 112 or 122 is provided todraw the sides of the slit toward each other, thereby contracting thesaid hole in diameter. In the drawings, although not necessarily in thecase of all embodiments of the different feattues of the invention, theclamping-lever 11 makes contact directly with the presser-bar 1. SeeFig. 3.

Movement is transmitted to the primary or clamping-lever 11 from thesecondary or actuator-lever 12, for the purpose of causing thepresser-bar to be gripped by the clamp. The two lever-members 11 and 12constitute in effect a compound lever. The arrangement of the saidlever-members, and the mode and means of their operative connection orengagement with each other, may vary more or less in practice. Thearrangement shown in the drawings is a convenient one. I usually placethe two lever-members in operative connection or engagement with eachother, for the purpose of transmitting movement from the actuatorlever12 to the clamping-lever 11, by means of a strut, as 131, Fig. 3,interposed between the said levermembers. The said strut is shown formedwith enlarged and rounded ends, the lever-members being represented asformed with concave seats receiving the said ends, makingknuckle-joints. Preferably, one or each of the seats in thelever-members is proportioned to take in somewhat more than half of theditIIlOtGlKOf the corresponding rounded enlarged end of the strut, theouter portions of the seat converging about the enlarged end somewhat soas to clasp the enlargement more than halfway around the same. Thisconstruction, while permitting free working of the end of the strut inthe seat during action, retains the said end within the seat, andprevents the strut from becoming detached and falling away, eitherduring the operation of assembling the parts or when the parts are beinghandled in setting or adjusting the same. The strut is applied to theseat, formed as just explained, by passing the enlarged end of the strutedgewise into the seat, and also is disengaged therefrom by an edgewisemovement. The actuator-lever 12 is operated by means of a tappet 13forming part of a rocker 14, which latter in the present instance isconveniently arranged at the outer end of head 3, the axis of the saidrocker extending horizontally, parallel with and across the said outerend. The rocker is mounted upon centerscrews 15, 15, which are appliedto lugs 31, 3], extending outwardly from the front and rear sides of thehead 3. For the convenient actuation of the rocker in proper timing withthe action of the other working parts of the machine it is in thepresent instance provided with an arm, 16, Figs. 1, 2 and i, which issleeved upon the rocker and made fast thereto by means ofclamping-screws 161, 161, Fig. 4, the said arm being joined by means ofa link 17, Figs. 2 and l, to ears projecting from one side of a collar18 which is mounted upon a vertically reciprocatory bar 19, hereinserving as an awl-bar and carrying an awl 10.1. The bar 19 has connectedtherewith actuating devices of suitable character, such devices in thepresent intance comprising a link 20 having its lower extremitypivotally joined to the collar 18, aforesaid, and a hub 21, providedwith a crank-pin having the upper extremity of the link connectedtherewith, and mounted upon the operating shaft 22 which is supported inbearings in the arm 01' gooseneck 1, all substantially as usual.

For the purpose of enabling the time of closing the clamp and beginningthe lift of the presser-bar, and also the extent of the lift of thepresser-bar and presserfoot, to be regulated when desired, the rockerand tappet 13 are made angularly adjustable around the axis of motion ofthe rocker. This adjustability is secured by flattening transversely, asshown in Fig. 2, the portion of the rocker 14 against which the innerends of the clamping-screws 16]., 161, bear, and by disposing the saidclamping-screws to make contact with the transversely-extending flatsurface of the rocker at opposite sides, circumferentially, of themiddle of the said surface. By turning the respective screws more orless the rocker and its tappet may be adjusted angularly with relationto the arm 16, and thereby the desired timing and extent of lift may besecured. 'lo obviate any tendency to lateral displacement of theactuator-lever 12, the rocker and top of the tappet .13 are grooved toreceive the said actuator-lever. An expanding spiral-spring 23,encircling the presser-bar 1, is confined between the top of the. sleeveor block 10 and the upper portion of the head 1%. it acts expansivelywith a tendency to move the clamp downward.

In operation, the rise of the awl-bar serves through the'connectionsbetween the same and the rocker to turn the latter in a manner to causethe tappet .13 to swing upwardly. In thus swinging, the said tappetpresses upwardly against the actuator-lever 12. The rise of the clampbeing resisted by the spring 223, the pressure of the tappet acts toturn the actuatonlevcr upon its pivotal connection with the cheeks 102,J02, and close the clamp firmly against the resser-bar. Further movementof the actuator-lever upon the pivot-pin 121 being then impossible, theclamp is raised bodily, carrying with it the presser-bar andpresser-foot and compressing the springs 5 and 225. As the tappet swingsdownwardly after completing its upward movement, it lowers the clamp,presser-bar, and presser-foot, which descend in unison until thepresserfoot seats itself upon the material being operated upon. Thisrelieves the clamp of the force exerted. by

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spring 5, and relaxes the pressure of actuator-lever 12 against thetappet, the pressure still remaining being only that which is due to theaction of spring 23 and to the weight of the clamp. Thereby the hold ofthe clamp upon the presser-bar is relaxed, and the clamp is permitted tofollow the tappet 13 down. In order to insure the complete release ofthe presser-bar, the actuator-lever is furnished with a heel 123extending to the opposite side of the pivotal axis of the actuator-leverfrom the portion of the latter upon which the tappet acts in clampingand lifting. As the parts complete their descent the said heel comesinto contact with an inner portion of the tappet, thereby causing theactuator-lever to be turned so as to open the clamp fully.

The acting surface of the tappet makes rolling contact with theactuator-lever 12, and as the tappet completes its downward swing thesaid actuator-lever comes gradually to take bearing against the portionof the tappet at its axis of movement, while in the upward swing of thetappet the lifting of the actuator-lever is gradually begun andcontinued. In consequence, the entire clamp is at all times supported onthe tappet, and blows, thumping, etc., resulting from play orlost-motion between the tappet and lever are obviated. Preferably, theactuator-lever l2 and strut 131 are combined and arranged to acttogether on the principle of a toggle, in order to gain an increase ofpower. Still further power is secured by the employment of the secondarylever 11, and' by causing the strut to engage therewith at a point sosituated with respect to the pivotal axis of such lever, and to theradial distance from such axis of the part which makes contact with thepresser-bar, as to give effective leverage. This employment of acompound lever is of great value, practically, inasmuch at it remediesdeficiencies which exist when the clamp is provided with a simpleactuator-lever or the like. It heretofore has been proposed to employ ina lifting arrangement, in combination with a toggle, a block actuatedthereby and sliding in an opening in the side of the sleeve or block, toengage with the resser-bar. This construction gives an insufiicient holdupon the presser-bar for some uses, and is unreliable in its action inlifting the presser-bar, there being a tendency to' slip. In case thetoggle were set fine enough to overcome the tendency to slip, the togglewould look and fail to release the clamp so as to permit the latter tolet go. The compound-lever arrangement characterizing my presentinvention enables ample power to be secured for perfect action, withoutit being necessary to cause the middle joint of the toggle to approachso closely to the line connecting the outermost joints as to occasion atendency to lock.

The operative portion of tappet 13 extends from the axis of motion ofthe rocker toward the presserbar, and the arm of the actuator-lever thatis engaged by the said tappet extends from the pivot of theactuator-lever in the same direction. This enables the lifting forcewhich is transmitted from the upwardly swinging tappet 13 to act alonglines at the same side of the said pivot and axis, and also of thetoggle-joint, as the presser-bar, closely adjacent the presser-bar.There is very little tendency during the lift to spring the presser-barand cause the same to bind in its guide- .increased through this cause.

bearings in the head of the machine. Hence, the resistance which has tobe overcome in raising the presser-bar and presserfoot, and the wearbetween the presser-bar and its guidebearings, are not materially Theaction, in other words, is rendered easier than would be the case werethe lifting tappet arranged to act at the opposite side of the pivot andaxis aforesaid, the wear and tear of the presser-bar and its bearingsare much less, and less strain devolves on the parts through which theactuation of the lifting tappet is derived. The arrangement, also, isconsiderably more compact than it is possible to make one in which thelifting tappet and arm or lever engaged thereby extend outward from thepresser-bar, inasmuch as a certain distance is necessary to be occupiedin order to secure the length of levers, etc., requisite in attainingthe required power in the clamping action, and in attaining the requiredlength of lift.

It will be perceived that my improved devices are fitted for use inother connections beside sewing machines. Therefore, I do not in allcases restrict myself to the employment of the said devices in thelatter connection.

What I claim is:-

1. The combination with the bar, of the clamp pro vided with thecompound lever, acting with multiplied leverage in eii'ecting the grip,and comprising a clampinglever and an actuator-lever both carried by theclampbody, and means actuating said actuator-lever and operating theclamp to grip the bar and move the latter endwise.

2. The combination with the bar, and the tappet, of the clamp composedof the sleeve or block fitted to the said bar, and the compound leveracting with multiplied leverage in effecting the grip and comprising aclamping-lever and an actuator-lever, both pivotally connected with thesaid sleeve or block, the said clamping-lever engaging the bar and theactuator-lever in operative engagement with the clamping-lever anditself actuated by the tappet to operate the clamp and move the barendwise.

3. The combination with the bar, and the tappet, of the clamp providedwith the clamping-lever and with the toggle mounted upon the clamp-bodyactuating the said clamping-lever and itself actuated by the saidtappet.

4. The combination with the bar, and the tappet, of the' clamp providedwith a clamping-lever, and with a toggle actuating the saidclamping-lever and comprising an actuator-lever engaged by the saidtappet and a strut intermediate the actuator-lever and clamping-leverthe clamp ing-lever and actuator lever being carried by the clampbody.

5. The combination with the bar, of the clamp having a compound-lever,the latter carried by the clamp-body and the tappet transmitting forceto the said compound-lever along lines at the side of the pivot of thelever-n1ember engaged thereby which is toward the said bar, to therebyactuate the clamp and move the bar endwise.

6. The combination with the bar, and the clamp having a clampinglever,and a toggle in operative connection with the said clamping-lever, saidclamping-lever and toggle carried by the clamp-body of a tappettransmitting force to the said toggle along lines at the side of thetoggle-joint or knuckle at which the bar is located.

7. The combination with the bar, of the clamp having a compound levercarried by the clamp-body, and the tappet engaging with a member of thesaid compound lever to actuate the clamp and move the bar endwise, andsupporting the clamp at all times.

8. The combination with the bar, of the clamp provided with acompound-lever embracing a clamping-lever and an actuator-lever bothcarried by the clamp-body, and clampactuating means applying force tothe actuator-lever at the side of the fulcrum thereof at which the baris located.

I a comp ound-lever 9. The combination with the bar, of the clamp havingembracing a clamping-lever and an actuator-lever both carried by theclamp-body, and a tappet engaging said actuator-lever, supporting theclamp at all times, and transmitting force to the actuator-lever at thatside of the pivot of the actuator-lever at which the bar is located toclose the clamp and move the bar endwise.

10 The combination with the bar, and the clamp having a clamping-leverand a toggle in operative connection with the said clampingdever bothcarried by the clan1pbody, of a tappet transmitting force to the saidtoggle along lines at the side of the toggle-joint or knuckle at whichthe bar is located, and supporting the clamp at all times.

11. The combination with the bar, of the block, the clamping lever inconnection with the said block, the ac tuator lever also in connectionwith the said Meek, and carried thereby, and actuating means for thesaid actuator lever operating the same to cause the bar to be clampedand raised.

In testimony whereof I ailix my signature in presence 01' two witnessHENRY 1i. CUMRHNUS.

Witnesses:

Cims. F. RANDALL, Amxn TAIKR.

